The drill is a piece of mechanical equipment for drilling rock, mainly including a pneumatic down-the-hole drilling machine and a top impact hydraulic drill in the market now. The pneumatic down-the-hole drilling machine, with an impact mechanism down-the-hole hammer at the bottom, can transmit impact energy well and is simple in structure, simple and convenient to operate, straight in drilling and the like, but high in energy consumption, low in rock drilling speed and quick to be worn. The hydraulic drill, with the impact mechanism on the top, transmits impact energy by striking a drilling rod and gradually replaces the pneumatic and electrical drills due to its high energy utilization rate, high rock drilling speed, low environment pollution and easy automation. Therefore, the hydraulic rock drilling technology has been well popularized and applied in the fields, such as mine, hydropower and tunnel traffic. In a conventional hydraulic drill, the impact wave pulse is generated by an impact piston, specifically, the impact piston strikes a shank to transmit the impact wave to the drilling rod, and the drilling rod further transmits the impact wave to a drilling bit. Since the impact energy thereof is transmitted by striking the drilling rod, the impact energy transmitted to the drilling bit will be weakened with the lengthening of the drilling rod, so that the drilling hole is easy to deflect, the drilling precision is low and so on. In addition, the working principle of the conventional hydraulic drill is to make the impact piston move to and fro at a high speed in a cylinder to generate impact energy by hydraulic differential pressure. Under the limitation of a hydraulic component, the hydraulic drill is limited in impact energy, thereby being not ideal in rock drilling operation of the large diameter drilling hole and deep hole, as shown in the Chinese invention named “rock drilling method and drill” with the application number of 200780041358, and the Chinese invention named “impact device and drill including the same” with the application number of 200780002786. In addition, some top impact hydraulic drills adopt a double-layer casing to reduce the deflection degree of the drilling hole, such as Coprod of Atlas Copco, and it only improves the top impact drill rather than improving the effect substantially.